Some Foundational Problems in Interdomain Routing

The substantial complexity of interdomain routing in the Internet
comes from the need to support flexible policies while scaling to a
large number of Autonomous Systems. Despite impressive progress in
characterizing the various ills of the Border Gateway Protocol
(BGP), many problems remain unsolved, and the behavior of the routing
system is still poorly understood. This paper argues that we must
understand interdomain routing in terms of: (1) intrinsic properties and
design tradeoffs of
policy-based routing, independent of the
specific routing protocol and
(2) properties that relate to artifacts in today's
protocol. We pose open questions for the research
community that, if answered, should help us understand why BGP's many
problems are so difficult to fix.
Understanding the fundamental properties of interdomain routing will
help us decide how to make progress, be it making backward-compatible
modifications to BGP or designing a radically different protocol.